1. Field of the Invention
The present invention relates to an audio data processing device, and particularly relates to an audio data processing device including a first processor and a second processor.
2. Related Background Art
In a portable device, the operating time by a battery and heat generation are large problems. Usually, to avoid these problems, a low-power-consumption and low-heat-generation CPU is used in the portable device. Such a low-power-consumption and low-heat-generation CPU is more powerless than a CPU used in a personal computer. However, in such a powerless CPU, it is extremely difficult to perform highly loaded operations at the same time, for example, to display non-compressed images simultaneously while reproducing audio data.
Meanwhile, there is slide show application software used by installing a program in a personal computer. A slide show is a function of displaying plural images while switching the images at a predetermined timing, and in some cases the slide show additionally includes a function of simultaneously reproducing desired audio at a predetermined timing. In Japanese Patent Application Laid-open No. 2001-339682 and Japanese Patent Application Laid-open No. 2002-189539, a method of reproducing audio simultaneously while sequentially displaying plural digital images, which are photographed and stored by a digital camera alone, by a built-in display device is disclosed.
However, the simultaneous reproduction of images and audio imposes a large load on the CPU, and then heat is generated. In an image display device which is carried, heat generation hinders its carrying, function, which impairs user-friendliness. To prevent heat generation, an energy-saving and high-speed CPU is needed, but it costs a lot and thereby its commercialization is difficult.
Hence, there is a technique of distributing processes between the CPU and a DSP (Digital Signal Processor). However, the mere distribution of processes sometimes causes a delay to either the reproduction of images or the reproduction of audio. Namely, since respective processing load conditions of the images and the audio change every moment, in some cases, either of the CPU and the DSP which share the processes is temporarily brought into a high-load condition depending on the timing, which causes a waiting time until the high-load side process is completed.
In some cases, this results in non-smooth unnatural reproduction without the images being smoothly reproduced, or slow key response since processes other than those of images/audio are delayed. In a series of processes in the simultaneous reproduction of images and audio, an image file reading process and an audio reproduction process have specially high loads, whereby when these processes are overlapped, an image display process and the like are influenced.
On the other hand, there is a method of reducing the amount of data by cutting off high-frequency components, but this method is intended only to reduce the entire amount of data, and not intended to reduce the load on the CPU in a high-load condition in the distributed processes between the CPU and the DSP.